feat(flake)!: move agenix-rekey module to auto.configurations

modules/flake/configurations/agenix-rekey/default.nix

@@ -3,6 +3,8 @@
   config = {
     # NOTE: `(r)agenix` and `agenix-rekey` modules are imported by `../../../modules/flake/configurations.nix`
     age.rekey = {
+      # NOTE: defined in `meta.nix`
+      # hostPubkey       = null;
       masterIdentities = lib.mkDefault [ "${inputs.self}/secrets/privkey.age" ];
       storageMode      = lib.mkDefault "local";
       localStorageDir  = lib.mkDefault "${inputs.self}/secrets/rekeyed/${config.networking.hostName}";

modules/flake/configurations/default-generators.nix

@@ -63,6 +63,7 @@ let
       (lib.optionalAttrs (meta ? pubkey) {
         age.rekey.hostPubkey = meta.pubkey;
       })
+      ./agenix-rekey
       # nix-topology
       inputs.nix-topology.nixosModules.default
       # Sane default `networking.hostName`